Microsoft is expanding the push for so-called "white spaces" broadband to South Africa, where it will help to deploy the technology in a pilot project serving five primary and secondary schools.

The pilot project is aimed at getting schools in rural parts of the country's northeastern Limpopo province connected to the Internet. If successful, it could give South Africa a tool that would help the country reach its goal of affordable broadband for 80 percent of the population by 2020.

White spaces are unused frequencies in TV bands, which Microsoft, Google and others advocate making available on an unlicensed basis for wireless broadband. Advocates won approval for that use in 2008 in the U.S., which was the first country to authorize white spaces. To ensure the new networks use only the slivers of spectrum in between licensed uses, devices need to have a database of licensed users and sensors to detect other activity in the band.

Commercial white-spaces networks are just starting to get off the ground in the U.S., but Microsoft has talked with governments in at least 50 other countries about the possibility of making such frequencies available, said Paul Garnett, Microsoft's director for technology policy.

TV channels are in the same general area of the spectrum band worldwide, so widespread use of white spaces could create a market for mass-produced, low-cost wireless devices, Garnett said. Africa, with more than 1 billion, could play a big role in making that happen, he said.

"That's a huge market, so if there are ways for us to expand access in those markets, then yes, that absolutely helps to create that global marketplace that any new technology is looking for to scale," Garnett said.

Just as the U.S. did, countries across Africa are converting their TV networks from analog to digital, which makes broadcasting more efficient and frees up some of the bandwidth for other uses. But in South Africa, there also are more frequencies in that band that haven't been claimed for anything, he said. That might create an easier path for unlicensed white spaces, which in the U.S. faced strong opposition from TV broadcasters and some other wireless users. South Africa is still evaluating whether to authorize unlicensed white-spaces networks, Garnett said.

"It's an even bigger opportunity ... for this kind of access to radio spectrum than exists in the U.S. or the U.K.," he said. For example, while some U.S. residents suffer from slow DSL (digital subscriber line) speeds, they at least have copper phone lines. Some parts of Africa have no connectivity at all, he said.

In the South African project, Microsoft will work with the University of Limpopo, government agencies and a local network builder called Multisource. The project will set up a central white-spaces radio at the university and one at each of the five schools.

At the schools, the project will give laptops to teachers and make tablets available in a classroom for students. Those clients will talk to special Wi-Fi access points that connect on the back end to the local white-spaces radio. Each school's radio will in turn connect to the Internet through the main white-spaces radio at the university, which has a fiber network.

Though each school's white-spaces radio will have a range of about 10 kilometers, initially they are intended only for use in the schools.

The project will also provide projectors, training and educational content, as well as solar panels where electricity is unavailable or unreliable, Garnett said.

The Limpopo project is part of a broader Microsoft initiative called 4Afrika, which has also included a white-spaces effort in Kenya.